I have two ready-to-upload scans of pieces that are definitely on the copyright borderline.

The first one is the 1949 version of Schoenberg's 5 Pieces for Orchestra, editied by Richard Hoffmann in 1972 (published by Peters in 1973). I would think it qualifies as urtext if it weren't for two things: the first edition of the 1949 version, published in 1952, was also edited by Hoffmann. Also, from what I can tell, Richard Hoffmann is still alive, living in Ohio. The footer of the first page of the score reads:

(Funny because there is definitely a preface by Hoffmann dated 1972 talking about the revisions.)

The second one is the full score to Berg's Lulu. It has two acts and an appendix ("anhang") containing a Variationen and an Adagio (definitely not the Cerha completion). Unlike the Wozzeck score it doesn't have any problematic English translation. The footer of the first page reads:

I think the music for Lulu might be OK in general (urtext is probably not needed) but probably not the Schoenberg because of possible additions made by the editor (sans any prefaces, these definitely have to be removed from the files).

Can I ask what kind of contributions does the editors include within the scores or is it not clear? If not clear, include the preface, then we can take a look to see what he did. It will have to remain blocked until we determine the copyright status on them. Very valuable to have these!

I uploaded the preface and score to the Schoenberg as separate files. (You can yank the preface when you're done, or both of them if it's not PD.) It has both the 1952 and 1972 remarks by Hoffmann, but the 1952 page seems to indicate that he didn't edit much at all besides measure numbers, Hauptstimme/Nebenstimme marks, and metronome marks.

The Lulu has no explanatory preface. Funny story: After I first posted this thread, I did some more searching that I probably should have done before asking here. I checked the Lulu page history and saw that back in 2014 you tried to upload what is probably the same score I have. Also this discussion happened, and the files were deleted with the remark "Apostel/Cerha edition." There's no way to tell how much Apostel and Cerha modified the first two acts that Berg finished, but it's frustrating that they might have heavily tweaked an edition only meant to have the parts that Berg finished. We might be SOL again. Let me know what you think.

That score I uploaded, I found on a Russian website. But it was the Cerha edition which had the completed third act, which is under copyright everywhere. It was at a time in my user infancy when I did not know very much about copyright compared to right now, which I know far more than I did two and a half years ago! And is now why I am a copyright reviewer.